Unveiling the Structural Properties of Lignin–Carbohydrate Complexes in Bamboo Residues and Its Functionality as Antioxidants and Immunostimulants

Abstract

Lignin–carbohydrate complexes (LCCs), a significant component of plant cell walls, have been found to bear biological functionality as antioxidants in food and as immunostimulants for living cell. In this work, a lignin-rich and a carbohydrate-rich LCCs preparations were isolated from bamboo residues (bamboo green and bamboo yellow). Each preparation was characterized by chemical composition and LCCs linkage types and quantities by high performance anion exchange chromatography (HPAEC) and NMR technologies (quantitative 13C NMR and 2D-HSQC NMR). Furthermore, evaluation of each LCCs preparation’s suitability as antioxidant and immunological substances were explored. Antioxidant assays indicated that all the LCCs preparations exhibited pronounced antioxidant activities for scavenging the 2,2-diphenyl-1-picryl-hydrazyl and hydroxyl radicals, while the lignin-rich LCCs outperformed the carbohydrate-rich LCCs. Immunological analysis showed that carbohydrate-rich LCCs could significantly inhibit the growth of breast tumor cells (MCF-7), while lignin-rich LCCs could stimulate the growth of macrophage cells (RAW 264.7). These results imply that LCCs extracted from bamboo may be used as novel and natural antioxidants or immunostimulants.

Lignin Carbohydrate Complexes structure preserved throughout downstream processes for their valorization after recovery from industrial process water

“…For quantification of LILs and LCLs, the aromatic regions (105-160 ppm) of all spectra were integrated and normalised to 600 resulting that the integral values of the other regions were expressed per 100 aromatic rings. Those integrals were used to convert the relative signals elucidated by 2D-HSQC into 13 C based number per aromatic rings (n°/100ar) as previously reported in the literature. 4,6,17,34 Calculations were done using the following equations (1) and (2):…”

“…8,9 Their biological properties were as well described in various papers including their antioxidants and anti-UV efficacies for cosmetic development and their pharmacological activities for human medicine. [10][11][12][13] For industrial purposes, it has been demonstrated that LCCs could be recovered from various residual feedstocks of lignocellucosic biomass. Narron et al deciphered their presence in the hydrolyzates resulting from the autohydrolysis pretreatment of hardwood and nonwood biomasses.…”

“…Samples were taken after the different DSP and compared to a freeze-dried control. Global and structural characterizations given by elemental analysis, acid hydrolysis, pyrolysis coupled to gas-chromatography, SEC, 13 C and 2D-HSQC NMR showed that the LCCs structure is well preserved during all of these DSP. This paper demonstrates the feasibility of producing high quality industrial LCC grade for commercialization in integrated biorefineries.…”

Structural features, interaction with the gut microbiota and anti-tumor activity of oligosaccharides

“…112 Studies have shown that LCCs may be involved in the induction of anti-tumor, anti-microbial, anti-HIV and antioxidation activity. 112,114,115 Polysaccharide portions of LCCs are composed of various types of sugars, such as glucose, arabinose, mannose, galactose, fucose and xylan. 114 LCCs from bald cypress, birch and rice straw show an extremely broad molecular weight distribution from 1.5 to 85 kDa.…”

The Microstructure and Mechanical Properties of Poplar Catkin Fibers Evaluated by Atomic Force Microscope (AFM) and Nanoindentation

“…They studied how to inhibit the production of PCFs, but not how to utilize them. There are few studies on the microstructure and mechanical properties of PCFs.In recent years, microscopic imaging and spectral characterization methods have been used in nanostructure and chemical composition analyses of cell walls of plant fibers like wood fibers [11][12][13][14][15][16], bamboo fibers [17][18][19][20][21][22], and cotton fibers [23,24]. Chen et al [25] characterized the aggregation of microfibrils in the cross-section of thin-wall cells using the atomic force microscopy (AFM) technique.…”